This invention relates to credit card size devices which include microprocessors and memory, often referred to as Smart Cards. In particular this invention relates to those cards required for secure transactions, and which require a large local data storage capability. Smart Cards are widely used in Europe as bank cards, health insurance cards, debit cards, and phone cards. They are also used to provide access to corporate networks and for other similar applications. The Smart Card architecture is conventionally based upon the ISO 7816 standard and requires a reader mechanism, in which the Card must be placed, for operation. This reader mechanism has minimal functionality, with all of the data processing and storage being performed by the microprocessor and memory in the Smart Card. The ISO 7816 interface utilizes six (6) contacts which are arranged on the surface of a the plastic card and allow data to be exchanged, usually at a maximum speed of about 116 kilobits per second.
Smart Cards are commercially available as memory only cards with 1 kilobyte (KB) to 256 KB of read/write storage; or with a microcontroller usually based on the 8051 or ARM architecture. The microcontroller based Smart Cards cost more and provide on-card data processing to achieve high security. The computing power, storage capacity and the speed at which data can be exchanged is limited by the electronic in the card, all of which must be contained within a thin plastic structure. The relatively high cost of these cards has limited their popularity in the United States, with the result that cheap magnetic stripe credits cards with 140 bytes of read only storage remain the dominant instrument for consumer credit/debit transactions, driver licenses, and access controls to facilities and networks.
A Smart Card with both a USB and ISO 7816 interface has been developed. For example, see the e-gate Smart Cards sold by Axalto. Another Smart Card sold by Sharp Inc has a microcontroller additional digital logic to support a USB interface and 1 MB of Flash memory storage. USB data transfer is implemented utilizing the remaining two contacts in the eight pad Smart Card connector with a maximum data transfer speeds of about 1.5 Mbits/second because of power and heat limitations. Such performance is considered slow for a content download device in which entertainment or other information is stored on the device for presentation to a user. Although the microcontroller for these newer cards is more powerful than in prior generations, the throughput is poor for emerging applications such as digital right management.
The growth of the Internet as a delivery medium has created a need for a local data storing card with large capacity, and which is secure, rugged and as convenient as a Smart Card, but has fast data transfer speed for quick transaction times and “off-line” debit/credit transaction capability.